Spectral Sidelobe Properties of Bipolar and Polyphase Spreading Codes in MC-CDMA Systems

In this thesis, the relationship between spectral sidelobes property of transmitting MC-CDMA signal and employed spreading code is investigated. Precisely, if the spreading codeword makes transmitting signal have continuous derivatives up to -th order all the time, the corresponding spectral sidelobes decay asymptotically as , where is a nonnegative parameter related to spreading codeword. For bipolar spreading code, the spectral sidelobe decaying behavior resulting from OVSF and OCG spreading code can be described by their codeword index. Similarly, for polyphase spreading code, the spectral sidelobe decaying behavior resulting from DFT and Zadoff-Chu spreading code can be described by their codeword index, too. Accordingly, with these descriptions, it can establish sidelobes suppression scheme during codeword assignment.